Passengers May Have A Lethal Effect On Teen Drivers

March 21, 2000 (Atlanta) -- Teen-agers, for the most part, are very social creatures. They like to congregate -- on corners, in cafeterias, and in cars. But when it comes to packing a car with friends, the more, the deadlier, according to a new study.

"The more passengers there were [in the car], the higher the death rates for 16- and 17-year-old drivers," Li-Hui Chen, PhD, the lead researcher on the study from the Johns Hopkins University School of Public Health, tells WebMD.

Chen writes in the March 22 issue of TheJournal of the American Medical Association (JAMA) that "motor vehicle crashes are the leading cause of death among teen-agers in the United States and carrying passengers has been identified as a possible risk factor for these crashes."

One way states are trying to deal with the high death rate among teens is by instituting graduated licensing systems. Essentially, this means new drivers must go through three stages before they earn a full-privilege license. Within each of those stages, certain restrictions may be placed on the young driver, depending on the state.

"There are about 24 states who have graduated licensing systems, and only nine of them have any restriction on passengers ... and I think both are needed," Chen tells WebMD. Even among those nine states (California, Delaware, Georgia, Indiana, Massachusetts, New Jersey, New Mexico, Oregon, and Wisconsin), the restrictions have wide variations, with some specifying the number of passengers but not their ages.

The researchers examined government statistics from 1992 to 1997, identified crashes in which 16- and 17-year-old drivers were killed, then scrutinized characteristics of the drivers and their passengers. Driver age and sex, the number of passengers, passenger age and sex, and the time of day of the accident all were considered.

The researchers found that the rate of deaths of 16- and 17-year-old drivers increased dramatically with the number of passengers they had in the car. The highest rate was among 16-year-olds with more than three passengers, 5.61 deaths per 10 million trips. For drivers with one passenger, the rate dropped to 2.76, and when the driver was alone in the car, the rate fell to 1.99 deaths per 10 million trips.